1. Technical Field of the Invention
This invention relates to telecommunication systems and, more particularly, to a system and method of providing a prepaid subscriber service in a packet-switched radio telecommunications network and in an integrated circuit-switched and packet-switched radio telecommunications network.
2. Description of Related Art
Prepaid subscriber service is currently provided only in circuit-switched radio telecommunications networks. Prepaid service keeps track of an account balance for a subscriber and subtracts charges from the account balance as the subscriber uses phone service. In order to do this effectively, a technique for calculating charges in near real time is required. In this way, if the subscriber depletes his prepaid account balance, the network denies him access if he tries to make further calls. In addition, if the prepaid account balance is depleted during an ongoing call, and the subscriber does not hang up, the network disconnects the call.
There are several ways of providing near real time billing information in circuit switched networks. For designated prepaid subscribers, a Call Data Record (CDR) may be output either immediately after a call is disconnected or at periodic intervals during the call. A Subscriber Type field is defined in the subscriber record in the subscriber""s Home Location Register (HLR) and is used to designate a prepaid subscriber. The Subscriber Type field is transferred to the Visitor Location Register (VLR) or Mobile Switching Center (MSC) serving the subscriber. The Subscriber Type field indicates to the serving node that the subscriber has a prepaid subscription.
Under regular billing procedures, a complete CDR is sent out at the end of a call to an associated storage system. CDRs are stored and accumulated there for a set amount of time which is configurable by the operator. For example, the call data records may be accumulated for 24 hours before being sent to a billing center where the subscriber is charged. For prepaid subscriber service, the process is accelerated in the circuit-switched network. The MSC recognizes the Subscriber Type field and provides partial CDRs during each call for the prepaid subscriber directly to a prepaid center, or through a billing gateway to the prepaid center. The amount of time between partial data records is configurable, for example, 5 minutes, 15 minutes, etc. Partial CDRs contain the same information as a complete CDR, but are sent out more rapidly and may cover only part of the call. The partial CDRs bypass the storage system so that charging information can be calculated in near real time.
The prepaid center includes rate information and converts call duration to a charge. It also subtracts the charges from the account balance as the call progresses in order to determine the subscriber""s account balance in near real time. If the balance reaches zero and the call is still ongoing, the prepaid center sends an instruction to the HLR to remove the subscriber""s subscription. This has the effect of disconnecting the call since it triggers the HLR to send a message to the MSC telling it that the subscription has been erased. The MSC then disconnects the call.
The existing method of providing prepaid service, however, has several disadvantages. First, the Subscriber Type field described above is a manufacturer""s proprietary field which is recognized only by network nodes manufactured by the specific manufacturer implementing the field. A standardized method is needed. Second, the existing method has only been used in circuit-switched wireless networks, and there is no known method of providing prepaid subscriber service in a packet-switched network.
In order to overcome the disadvantage of existing systems, it would be advantageous to have a standardized system and method of providing prepaid subscriber service in both circuit-switched and packet-switched radio telecommunications networks. The present invention provides such a system and method.
In one aspect, the present invention is a method of providing a prepaid subscriber service to a mobile subscriber in a wireless packet-switched telecommunications network such as the General Packet Radio Service (GPRS). The method includes the steps of storing a prepaid subscriber class (PPSC) in a home location register (HLR) in the network, and sending the PPSC from the HLR to a Serving GPRS Service Node (SGSN) when the subscriber registers. When the subscriber begins a data session, the SGSN periodically sends partial call data records (CDRs) during the data session to a prepaid center (PPC). The partial CDRs may cover charges for radio network usage. A Gateway GPRS Service Node (GGSN) may send partial CDRs covering data network usage. This is followed by calculating in the PPC in near real time, a new account balance for the subscriber, and ending the data session when the account balance is reduced to zero.
In another aspect, the present invention is a method of providing a prepaid subscriber service to a mobile subscriber in an integrated wireless telecommunications network having a circuit-switched portion and a packet-switched portion. The method includes the steps of storing the PPSC in the HLR in the network, sending the PPSC from the HLR to an MSC serving the prepaid subscriber when the subscriber registers in the circuit-switched portion of the network, and sending the PPSC from the HLR to a packet-switched service node serving the prepaid subscriber when the subscriber registers in the packet-switched portion of the network. Also, the PPSC may be sent inter-nodally from one packet-switched node to another, for example, from a serving node to a gateway node, at a Packet Data Protocol (PDP) context activation. Upon beginning a circuit-switched call by the mobile subscriber, the MSC periodically sends partial CDRs to the PPC. Upon beginning a packet-switched data session by the mobile subscriber, the packet-switched service nodes, for example, both serving and gateway nodes, periodically send partial CDRs to the PPC. This is followed by calculating in the PPC in near real time, a new account balance for the prepaid subscriber, and stopping the prepaid subscriber service when the account balance is reduced to zero.
In yet another aspect, the present invention is a method of providing a prepaid subscriber service to a mobile subscriber in a wireless packet-switched telecommunications network which includes sending a Subscriber Type field in a message from the HLR to a packet-switched service node serving the mobile subscriber when the subscriber registers with the service node. Also, the Subscriber Type may be sent inter-nodally from one packet-switched node to another, for example, from the serving node to a gateway node, at a Packet Data Protocol (PDP) context activation. Upon beginning a packet-switched data session by the mobile subscriber, the packet-switched nodes, for example, both serving and gateway nodes, periodically send partial CDRs to the PPC. This is followed by calculating in the PPC in near real time, a new account balance for the subscriber, and ending the data session when the account balance is reduced to zero.
In a still further aspect, the present invention is directed to a method of providing a prepaid subscriber service to a mobile subscriber in an integrated wireless telecommunications network having a circuit-switched portion and a packet-switched portion. The method provides for creating in a home location register (HLR) in the network a subscription for at least one of a circuit-switched service and a packet-switched service, for the mobile subscriber. The method also creates in a prepaid center (PPC) an account for at least one of the circuit-switched service and the packet-switched service for the mobile subscriber. The method includes the step of sending a prepaid subscriber class (PPSC) in a message from the HLR to a Mobile Switching Center (MSC) serving the prepaid subscriber when the subscriber registers in the circuit-switched portion of the network. Further, when the subscriber registers in the packet-switched portion of the network, the prepaid subscriber class (PPSC) is sent via a message from the HLR to a serving packet-switched service node serving the prepaid subscriber. The PPSC may also be sent inter-nodally from one packet-switched node to another, for example, from the serving node to a gateway node, at a Packet Data Protocol (PDP) context activation. Upon beginning a packet-switched data session by the mobile subscriber, the packet-switched nodes, for example, both serving and gateway nodes, periodically send partial CDRs to the PPC. Also, upon beginning a circuit-switched call by the mobile subscriber, partial call data records (CDRs) are periodically sent from the MSC to the PPC. A new account balance for the prepaid subscriber""s account is calculated in the PPC in near real time, and the method stops at least one of the circuit-switched service and the packet-switched service when the account balance is reduced to zero.